Despite the fact that wooden walls retain heat better than concrete and brick, they also need high-quality insulation. Over time, the tree shrinks, cracks appear at the corners and at the seams, cracks form in the timber itself, through which cold penetrates into the house. Thermal insulation will help get rid of these problems, and at the same time will reduce heating costs, and significantly. But first you need to decide how to insulate a wooden house from the outside in order to maintain a comfortable microclimate in the premises and extend the life of the wood itself.
How to insulate a wooden house from the outside
Any wood has the ability to absorb moisture.
Treatment with various impregnations significantly reduces the hygroscopicity of the material, but cannot completely eliminate it. With normal ventilation, moisture evaporates efficiently without negatively affecting the material, and an optimal microclimate is maintained in the house. But the violation of air exchange leads to the accumulation of condensate and the swelling of the tree, as a result of which fungi develop in it, rot appears, the air in the house becomes musty.
Mold on the rough boards of the house frame
To avoid such problems, several rules should be followed:
Diagram of waterproofing and proper insulation of a wooden house
If the wooden walls are planned to be painted or you only need to insulate the seams, paint and sealant is also chosen for vapor-permeable, for example, acrylic-based.
And, of course, before insulation, the surface must be well prepared, cleaned of dirt, moss, mold, and repaired. It is especially important that there are no woodworm beetles in the walls, because under a layer of insulation they will continue their destructive activity until the tree becomes unusable.
Walls must not be insulated if a bark beetle has wound up
The choice of modern insulation is wide, but not all of them are vapor-permeable. Mineral wool materials and cellulose insulation, or ecowool, are most suitable for wooden houses. Let's consider their characteristics in more detail.
This insulation is produced from molten rocks , most often from basalt. In addition to stone fibers, the insulation contains a binder (formaldehyde resins, urea) and water repellents. Stone wool belongs to non-combustible materials, withstands heating up to 600 ° C without changing physical properties, has low thermal conductivity and high vapor permeability. It is produced in slabs and mats, and can be coated with foil, fiberglass and kraft paper.
Basalt slabs are quite dense and rigid, they perfectly retain their shape throughout the entire service life and almost do not shrink, provided that the thermal insulation is made according to all the rules.
Moreover, this insulation is resistant to microorganisms, which is also a great advantage. The correct shape and low weight of the slabs allow installation without much effort, moreover, basalt fibers are not prickly and do not cause irritation on the skin.
Mineral wool slab
As for the shortcomings, stone wool has very few of them. The main disadvantage is the fragility of the fibers - when squeezing and cutting the material, fine dust is formed, which easily penetrates the respiratory tract. Because of this, it is recommended to work with a respirator.
Another disadvantage is the high cost of insulation, so with a limited budget, you should look for other options.
The raw materials for the manufacture of this insulation are blast-furnace slags, that is, metallurgical waste, which leads to a low material cost. The thermal conductivity of slag wool is slightly higher than that of basalt insulation, and the maximum heating temperature is 300 ° C, after which the fibers begin to sinter and the material loses its characteristics.
Slag wool is produced in rolls and plates, often with a foil coating. It does not differ in rigidity, and therefore is excellent for thermal insulation of curved surfaces - it can easily be given any shape.
Slag wool holds heat well, effectively absorbs sounds, rodents and insects do not like it. Mold does not develop in such insulation either.
But slag wool also has enough drawbacks: it is hygroscopic, does not tolerate temperature changes, and when it gets wet, it releases acid that corrodes metal. Its brittle fibers are almost as sharp as glass wool, and therefore irritate when in contact with the skin. When installing the insulation, it is imperative to use protective equipment to avoid getting particles in the eyes and respiratory tract.
|Density||20-210 kg / m3|
|Water vapor permeability||0.25-0.35 mg / mhPa|
|Thermal conductivity||0.034-0.043 W / mK|
|Water absorption by volume|| 1. |
|Slab dimensions||1000x500 mm, 1200x600 mm|
|Service life||up to 50 years|
Glass wool is elastic and durable, perfectly dampens noise and has a thermal conductivity coefficient of 0.03-0.052 W / m * K
Insulation is made from melts of glass broken adding limestone, dolomite, borax and some other components. The binder is synthetic polymers, less often bitumen.Glass wool has the longest fibers (from 15 to 50 mm), due to which the material is noticeably superior in elasticity and resilience to other types of mineral wool, and also has a high mechanical strength at a low density.
Glass wool is vapor-permeable, retains heat well, is not afraid of the effects of chemically aggressive substances. It is non-flammable, withstands heating up to 450 ° C without changing its physical characteristics, it is not affected by sudden temperature changes. Like other mineral wool insulation, glass wool is produced in slabs, rolls and mats, including those coated with foil and fiberglass.
The biggest disadvantage of glass wool is the fragility and brittleness of the fibers, which can cause severe irritation to the skin and penetrate the respiratory tract and eyes.
Working with glass wool is quite difficult: the material is fragile and prickly
Light clothing cannot protect against fine and sharp particles, therefore, for work, you need to choose something denser, be sure to use a respirator, glasses and rough gloves.
Working with glass wool is allowed only with gloves
|Density||11-25 kg / m3|
|Vapor permeability||0-0.6 mg / mhPa|
|Thermal conductivity||0.029-0.041 W / m * K|
|Water absorption by volume|| 0.6-0. |
|Dimensions||1250x600 mm , 3900х1200 mm|
|Service life||20-25 years|
Cellulose insulation (cellulose wool, "ecowool")
For the production of ecowool, waste from the paper and cardboard industry is used, and 80% of this insulation consists of natural cellulose. To improve the characteristics, cellulose fibers are mixed with fire retardants and antiseptics. Ecowool has the ability to absorb and release moisture without changing the thermal insulation properties, and if you insulate the walls with it, condensation will never appear in the room. In addition, it absorbs sounds well, dampens vibrations, and does not emit harmful substances. Due to the presence of insecticidal additives, insects do not start in such a heater, and rodents rarely damage it.
Ecowool premium fiber
Insulation is a very loose light gray mass, which is tightly packed in bags of 15 kg. Immediately before insulation, the mass is poured out of the bag and loosened with a mixer, and then it is placed manually or by machine. The effectiveness of thermal insulation directly depends on the density of the layer: a weakly compacted material quickly shrinks and forms cold bridges, while a tightly laid coating does not change its characteristics throughout its entire service life.
Ecowool is an excellent building material
The main disadvantage of ecowool is the technology of its laying. A pneumatic installation is expensive and requires certain skills to work with it, so it is better to hire specialists for mechanical blowing.
Ecowool, flying out of the hose in a dry state, is moistened with water using nozzles
Manual laying takes a lot of time, the material is distributed less evenly, more physical effort is spent on ramming.
|Density||30-75 kg / m3|
|Thermal conductivity||0.032-0.041 W / m * K|
|Water vapor permeability||0.3 mg / mhPa|
|Service life||up to 50 years| Mineral wool
Mineral wool insulation does not require special skills and abilities, so everyone can cope with it if desired.
To do everything as efficiently as possible, you need to stock up on the necessary tools in advance, correctly calculate the amount of materials, and carefully prepare the surface.
Tip. New wooden houses are prone to shrinkage, therefore, it is best to start insulation and exterior decoration a couple of years after the construction of the structure.
In the process of arranging thermal insulation you will need:
Impregnation for wood
Vapor permeable membrane
To find out how many plates are required for insulation, you need to calculate the total wall area, subtract from it the area of the openings and divided by the area of one slab.
How to calculate the area of the walls
Usually slabs have standard dimensions 1200x600 mm, that is, the area is 0.72 m2. Having determined the estimated amount, you need to increase it by 5-7%, since part of the material will go to trimming near the openings. If the insulation is planned to be laid in 2 layers, the resulting number is multiplied by 2.
Dimensions of rolls and slabs of mineral wool
The lathing can be assembled made of metal profiles, but timber with a section of 50x50 mm is more suitable for wooden walls.
Beam 50x50 mm
For a double layer of insulation, take a beam with a section of 100x50 or 100x40 mm and install it on the edge.
Assortment of lumber
Lumber must be dry, even, without defects, before starting work it must be treated with antiseptic impregnation and dried.
Insulate the house outside should be dry warm weather so that the walls are not damp or frozen. The surface should be free from dirt, dust, moss, fungi and mold. Mezhventsovye seams must be carefully inspected and where there are voids, re-seal with a sealant and seal with a sealant.
Deep cracks in the tree itself are repaired in the same way.
Filling cracks in logs with sealant
The next step is priming. The primer is applied with a brush, carefully processing all the depressions, irregularities, end cuts of the logs. If the wood absorbs the composition too quickly, it is recommended to apply the primer in 2 coats. After that, you need to wait until the surface is completely dry and only then proceed to the main process.
Very convenient to apply primer using a spray gun
Impregnation for wood
Step 1. Attach the vapor barrier layer. The membrane is arranged in horizontal stripes starting from the bottom of the walls and is fixed with staple brackets. The upper fabric should overlap the lower one by 10-15 cm, the joint is glued with tape along the entire length.
Do not replace the membrane with regular plastic wrap. Polyethylene is vapor-proof, so fumes will settle on the walls with condensation, causing damage to the wood. The membrane is inexpensive and can be bought at any hardware store, so there is no benefit from using polyethylene.
Step 2. The extreme bars of the crate are set according to the level at a distance of 5-10 cm from the corner and screwed to the walls with self-tapping screws.
The rest of the guides are fixed so that the distance between them is 10 mm less than the width of the insulation. Each rack is controlled with a level so that all elements of the lathing are located in the same plane.
Lathing for mineral wool
Step 3. Plates of mineral wool are tightly placed in the cells of the crate, trying not to leave gaps, and then additionally fix with dish-shaped dowels. The second layer of insulation must be laid so that the joints between the plates of the first layer overlap.
Laying mineral wool slabs. In the photo, you can see the builders' mistake - the absence of an insulating membrane between the wool and the wooden wall
Fixing the mineral wool with dowels
Step 4. A protective membrane is again attached on top of the insulation, fixing in the same way with staples and gluing the joints with tape. The sheets of material should fit snugly to the base, without sagging and folds.
Fixing the membrane over the insulation
Next, the strips of the counter-lattice are packed, placing them perpendicular to the guides of the lower frame. These slats provide the necessary clearance for the ventilation of the insulation after the installation of the topcoat.
You can also use another method - frameless, when instead of timber guides, metal U-shaped suspensions are attached to the walls at an equal distance. In mineral slabs, neat slots are made with a mounting knife and the ears of the suspensions are threaded through them. Additionally, the insulation is fixed with fungal dowels.
From above, the thermal insulation is closed with a membrane, and a crate made of a bar or profile is mounted on the suspensions.
Vapor barrier material
Racks are fixed to the hangers with self-tapping screws
On the walls, markings are made for the crate and vertical guides made of timber are mounted. The distance between them is 50-60 cm. Further, the sheathing is performed with moisture-resistant OSB boards, but not to the full height, but about 80-100 cm from the ground. Be sure to sew up the bottom with boards.
Next, you need a large, wide container and a drill with a mixer attachment. Ecowool is unpacked, poured into a container, fluffed at low speed with a mixer so that no lumps remain.
The prepared insulation is poured between the wall and the cladding, and carefully tamped, carefully filling in the corners and recesses. When the cavity is filled almost to the top, the next row of cladding is attached, controlling the level of the location of the plates. The most difficult thing is to distribute the insulation at the very top of the crate, so you need to work slowly, very carefully, trying to tamp the material as much as possible.
After fixing the top sheets, the sheathing is primed and proceeding to the finishing.
Manual installation of ecowool
It is more effective to apply ecowool in a wet way using the installation. In this case, the rack guides are mounted in increments of 1-1.2 m. The insulation is poured into the container and water is added in small portions until the mass becomes sticky.
Further, using the installation, ecowool is applied to the walls in a continuous uniform layer and left to dry completely. Excess material protruding above the plane of the frame is carefully cut off. After the thermal insulation has dried, a windproof membrane is attached and a finish is made.
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